Background COVID-19 has rapidly evolved to become a global pandemic due largely to the transmission of its causative virus through asymptomatic carriers. Detection of SARS-CoV-2 in asymptomatic people is an urgent priority for the prevention and containment of disease outbreaks in communities. However, few data are available in asymptomatic persons regarding the accuracy of PCR testing. Additionally, although self-collected saliva has significant logistical advantages in mass screening, its utility as an alternative specimen in asymptomatic persons is yet to be determined. Methods We conducted a mass-screening study to compare the utility of nucleic acid amplification, such as reverse transcriptase polymerase chain reaction (RT-PCR) testing, using nasopharyngeal swabs (NPS) and saliva samples from each individual in two cohorts of asymptomatic persons: the contact tracing cohort and the airport quarantine cohort. Results In this mass-screening study including 1,924 individuals, the sensitivity of nucleic acid amplification testing with nasopharyngeal and saliva specimens were 86% (90%CI:77-93%) and 92% (90%CI:83-97%), respectively, with specificities greater than 99.9%. The true concordance probability between the nasopharyngeal and saliva tests was estimated at 0.998 (90%CI:0.996-0.999) on the estimated airport prevalence at 0.3%. In positive individuals, viral load was highly correlated between NPS and saliva. Conclusion Both nasopharyngeal and saliva specimens had high sensitivity and specificity. Self-collected saliva is a valuable specimen to detect SARS-CoV-2 in mass screening of asymptomatic persons.

Background COVID-19 has rapidly evolved to become a global pandemic due largely to the transmission of its causative virus through asymptomatic carriers. Detection of SARS-CoV-2 in asymptomatic people is an urgent priority for the prevention and containment of disease outbreaks in communities. However, few data are available in asymptomatic persons regarding the accuracy of PCR testing. Additionally, although self-collected saliva has significant logistical advantages in mass screening, its utility as an alternative specimen in asymptomatic persons is yet to be determined. Methods We conducted a mass-screening study to compare the utility of nucleic acid amplification, such as reverse transcriptase polymerase chain reaction (RT-PCR) testing, using NPS and saliva samples from each individual in two cohorts of asymptomatic persons: the contact tracing cohort and the airport quarantine cohort. Results In this mass-screening study including 1,924 individuals, the sensitivity of nucleic acid amplification testing with nasopharyngeal and saliva specimens were 86% (90%CI:77-93%) and 92% (90%CI:83-97%), respectively, with specificities greater than 99.9%. The true concordance probability between the nasopharyngeal and saliva tests was estimated at 0.998 (90%CI:0.996-0.999) on the estimated airport prevalence, 0.3%. In positive individuals, viral load was highly correlated between NPS and saliva. Conclusion Both nasopharyngeal and saliva specimens had high sensitivity and specificity. Self-collected saliva is a valuable specimen to detect SARS-CoV-2 in mass screening of asymptomatic persons.

Background Quantitative RT-PCR (RT-qPCR) of nasopharyngeal swab (NPS) samples for SARS-CoV-2 detection requires medical personnel and is time consuming, and thus is poorly suited to mass screening. In June, 2020, a chemiluminescent enzyme immunoassay (CLEIA; Lumipulse G SARS-CoV-2 Ag kit, Fujirebio, Tokyo, Japan) was developed that can detect SARS-CoV-2 nucleoproteins in NPS or saliva samples within 35 min. In this study, we assessed the utility of CLEIA in mass SARS-CoV-2 screening. MethodsWe did a diagnostic accuracy study to develop a mass-screening strategy for salivary detection of SARS-CoV-2 by CLEIA, enrolling hospitalised patients with clinically confirmed COVID-19, close contacts identified at community health centres, and asymptomatic international arrivals at two airports, all based in Japan. All test participants were enrolled consecutively. We assessed the diagnostic accuracy of CLEIA compared with RT-qPCR, estimated according to concordance (Kendall's coefficient of concordance, W), and sensitivity (probability of CLEIA positivity given RT-qPCR positivity) and specificity (probability of CLEIA negativity given RT-qPCR negativity) for different antigen concentration cutoffs (0•19 pg/mL, 0•67 pg/mL, and 4•00 pg/mL; with samples considered positive if the antigen concentration was equal to or more than the cutoff and negative if it was less than the cutoff). We also assessed a two-step testing strategy post hoc with CLEIA as an initial test, using separate antigen cutoff values for test negativity and positivity from the predefined cutoff values. The proportion of intermediate results requiring secondary RT-qPCR was then quantified assuming prevalence values of RT-qPCR positivity in the overall tested population of 10%, 30%, and 50%. Findings Self-collected saliva was obtained from 2056 participants between June 12 and Aug 6, 2020. Results of CLEIA and RT-qPCR were concordant in 2020 (98•2%) samples (Kendall's W=0•99). Test sensitivity was 85•4% (76 of 89 positive samples; 90% credible interval [CrI] 78•0-90•3) at the cutoff of 0•19 pg/mL; 76•4% (68 of 89; 68•2-82•8) at the cutoff of 0•67 pg/mL; and 52•8% (47 of 89; 44•1-61•3) at the cutoff of 4•0 pg/mL. Test specificity was 91•3% (1796 of 1967 negative samples; 90% CrI 90•2-92•3) at the cutoff of 0•19 pg/mL, 99•2% (1952 of 1967; 98•8-99•5) at the cutoff of 0•67 pg/mL, and 100•0% (1967 of 1967; 99•8-100•0) at the cutoff of 4•00 pg/mL. Using a two-step testing strategy with a CLEIA negativity cutoff of 0•19 pg/mL (to maximise sensitivity) and a CLEIA positivity cutoff of 4•00 pg/mL (to maximise specificity), the proportions of indeterminate results (ie, samples requiring secondary RT-qPCR) would be approximately 11% assuming a prevalence of RT-qPCR positivity of 10%, 16% assuming a prevalence of RT-qPCR positivity of 30%, and 21% assuming a prevalence of RT-qPCR positivity of 50%.Interpretation CLEIA testing of self-collected saliva is simple and provides results quickly, and is thus suitable for mass testing. To improve accuracy, we propose a two-step ...

Study Design: A sex- and age-matched case-control study and a cross-sectional study. Objective: In our previous study, patients with early-onset (<50 years of age) ossification of the posterior longitudinal ligament (OPLL) had distinct features such as morbid obesity, a high prevalence of lifestyle-related diseases, and diffuse ossified lesions mainly affecting the thoracic spine. Our goals were to determine whether early-onset OPLL patients have unbalanced dietary habits and to identify nutritional factors associated with OPLL exacerbation. Methods: In Study 1, the simple brief-type self-administered diet history questionnaire (BDHQ) was used to compare nutrient intake levels of early-onset OPLL patients (n = 13) with those of sex- and age-matched non-OPLL controls (n = 39) or with those of common OPLL (onset age ≥ 50 years, n = 62). In Study 2, serological validation was conducted for thoracic OPLL patients (n = 77) and non-OPLL controls (n = 101) in a nationwide multicenter study in Japan. Results: The BDHQ showed that the early-onset OPLL patients had significantly lower intakes of vitamins A and B6 than non-OPLL controls. These results were validated by lower serum vitamins A and B6 levels in the early-onset thoracic OPLL patients. The severity of OPLL negatively correlated with serum vitamin A levels in male early-onset OPLL patients. The multiple regression analysis revealed that the severity of thoracic OPLL had an association with onset age and serum vitamin A level. Conclusions: Vitamin A deficiency resulting from unbalanced dietary habits is associated with exacerbation of male early-onset OPLL.

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Background Dietary calcium has been proposed to reduce appetite in human studies. Postprandial satiety is mainly controlled by gut hormones. However, the effect of calcium on appetite and the role of gut hormones remain unclear. Objectives We examined whether oral administration of calcium reduces food intake in rats and investigated the underlying mechanism. Methods Male Sprague Dawley rats (8–12 wk old) were used after an overnight fastifffng. In a series of 2 trials with 1-wk interval between challenges, food intake was measured 0.5–24 h after oral gavage of a vehicle (saline containing 1.5% carboxymethyl cellulose) as the control treatment, or the vehicle containing various calcium compounds [calcium chloride (CaCl2), calcium carbonate, calcium lactate, in a random order] at 150 mg calcium/kg dose. A conditional taste aversion test was conducted. In separate experiments, plasma calcium and gut hormone concentrations were measured 15 or 30 min after oral administration of the calcium compounds. In anesthetized rats, portal peptide-YY (PYY) concentrations were measured after intraluminal administration of a liquid meal with or without additional calcium. Results Oral CaCl2 reduced food intake acutely (30 min, ∼20%, P &lt; 0.05) compared with control rats, without taste aversion. Plasma PYY concentration was higher (100%, P &lt; 0.05) in CaCl2-preloaded rats than in control rats, 15 min after administration. In anesthetized rats, luminal meal + CaCl2 induced a 4-fold higher increase in plasma PYY than the control treatment did. Oral administration of a calcium-sensing receptor (CaSR) agonist suppressed food intake (∼30%, P &lt; 0.05), but CaCl2 and CaSR agonist did not suppress food intake under treatment with a PYY receptor antagonist. Furthermore, the CaSR antagonist attenuated the effect of CaCl2 on food intake. Conclusions CaCl2 suppresses food intake partly by increasing CaSR-mediated PYY secretion in rats. Our findings could at least partially explain the satiating effect of calcium.

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